The effects of spirulina consumption added in foods were investigated in two crossover clinical trials (n = 13 different healthy adults). In Trial-1 adults consumed cookies with-and-without spirulina (3.12 g per 100 g final product; 2.5 g spirulina per 50 g available carbohydrates) according to glycemic index (GI) methodology. In Trial-2, adults consumed 4 g, 6 g, and 8 g spirulina as beverage diluted in 50 g D-glucose vs. 50 g plain D-glucose. Capillary blood glucose samples were collected at 0, 15, 30, 45, 60, 90, and 120 min and blood pressure (BP) was measured at beginning and end of each visit in both trials. Trial-1: both cookies with and without spirulina provided medium GI values (59 and 60, respectively, on glucose-scale), but no significant differences were found for BP. Trial-2: both 4 g and 8 g spirulina lowered postprandial glucose at 120 min (95% CI: −1.64 to −16.12 and −1.23 to −15.87, respectively). The results explained 29% of variation. Only 8 g spirulina decreased significantly 90–120 min area under the curve (AUC) for glucose and systolic BP (−4%). No differences were found for fasting glucose. Adding spirulina to cookies did not affect glucose responses and BP. Only 8 g provided significantly lower 90–120 min-AUC for glucose and BP compared to 4 g, 6 g-and-D-glucose, indicating advantages to glycemic control and hypertension.